bmp280 datasheet

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Sensortec | BMP280 Data sheet
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Modifications reserved | Data subject to change without notice
Document number: BST-BMP280-DS001-23 Revision_1.23_11202
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5.2.2 I²C read
To be able to read registers, first the register address must be sent in write mode (slave address
111011X0). Then either a stop or a repeated start condition must be generated. After this the slave is
addressed in read mode (RW = ‘1’) at address 111011X1, after which the slave sends out data from
auto-incremented register addresses until a NOACKM and stop condition occurs. This is depicted in
Figure 8, where two bytes are read from register 0xF6 and 0xF7.
Start RW ACKS ACKS
1 1 1 0 1 1 X 0 1 1 1 1 0 1 1 0
Start
RW ACKS ACKM NOACKM Stop
1 1 1 0 1 1 X 1 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
Control byte
Data byte
Data byte
Register address (F6h)
S
Slave Address
P
S
Slave Address
Register data - address F7h
Register data - address F6h
Figure 8: I²C multiple byte read
5.3 SPI interface
The SPI interface is compatible with SPI mode ‘00’ (CPOL = CPHA = ‘0’) and mode ‘11’ (CPOL =
CPHA = ‘1’). The automatic selection between mode ‘00’ and ‘11’ is determined by the value of SCK
after the CSB falling edge.
The SPI interface has two modes: 4-wire and 3-wire. The protocol is the same for both. The 3-wire
mode is selected by setting ‘1’ to the register spi3w_en. The pad SDI is used as a data pad in 3-wire
mode.